This invention relates to a system for monitoring the performance of a vehicle during operation and, more particularly, to a system which monitors the performance of a vehicle during operation by measuring the total time during which the vehicle is operated under conditions which cause the vehicle operation parameters to exceed preselected threshold values. This invention further relates to a system for monitoring the performance of a vehicle capable of providing real time information related to the operation of the vehicle under conditions exceeding vehicle operation threshold values.
It is well known that the manner in which a vehicle is operated on the road by its driver is largely responsible for both the degree of wear and tear on the vehicle as well as the economic efficiency of the vehicle operation. This is the principal reason instrument gauges such as the speedometer, tachometer and others are included for providing a real time visual display containing information related to the efficiency of the vehicle operation. For example, the speedometer and tachometer typically include a visual display indicative of the vehicle speed and engine operating speed. The driver, cognizant of the fact that continued high vehicle speed or high engine operating speed could result in unnecessarily inefficient vehicle operation, would then reduce vehicle speed or engine operating speed to improve vehicle efficiency. Efficient vehicle operation is particularly desirable in large scale, multiple vehicle operations such as trucking lines where the maximization of efficient vehicle operation would result in significant savings.
A traditional problem for multiple vehicle operations achieving improved vehicle operating efficiency is that some vehicle operators tend to disregard recommendations which would achieve improved vehicle efficiency. A need has arisen, therefore, for a method of determining how efficiently a driver is operating the vehicle.
One of the earliest vehicle monitoring systems developed involved the use of a "tach chart". During the operation of a vehicle, the output of the tachometer would be recorded on a chart as a function of time. The chart produced could then be utilized to evaluate how efficiently the driver had operated the vehicle over a period of time. Periods of inactivity, idling, or over-revving of the engine could be readily determined upon analysis of the chart. Such devices were, however, unable to record tachometer output over long periods of time due to physical limitations on the size or length of the recording medium. Thus, monitoring devices were of little use in vehicle operations where a single vehicle would be on the road for weeks at a time. Furthermore, tach chart devices were unable to distinguish between drivers when multiple drivers operated the same vehicle being monitored on a single trip. Common driver practices, for example, the practice of "slip seating" where two drivers assigned to a single vehicle will exchange seats during the trip, would reduce the usefulness of the collected data. While analysis of the data would provide information on the efficiency of the vehicle operation, slip seating and other driver practices would make the recorded data useless in evaluating the performance of specific drivers.
In recent years, the use of computers and other processing devices in vehicle performance monitoring systems have become popular. Typically, computer-based vehicle performance monitoring systems include multiple sensors for determining a number of vehicle operating characteristics indicative of the efficiency of the operation of the vehicle. The data would be stored in an on-board memory system and, at the completion of the trip, the on-board memory system would be plugged into a host computer. The stored data would be dumped into the host computer for subsequent analysis of the efficiency with which the driver had operated the vehicle. Unfortunately, such computer-based monitoring systems can easily cost two to three thousand dollars per vehicle. To outfit an entire fleet of vehicles, therefore, would represent a substantial investment, often in excess of what the industry is willing to pay.
Furthermore, the computer-base monitor system was not particularly useful in assisting drivers to improve the efficiency of their driving. Typically, performance reports were not available for review by the driver until long after the trip had been completed and when the driver's memory was sketchy. Computer-based vehicle performance monitoring systems also generally fail to provide immediate feedback to the driver of how efficiently the vehicle is being operated each moment. This failure to provide sufficient guidance to the driver on how to optimize the performance of the vehicle renders the system unable to train the driver how to operate a vehicle to maximize driving efficiency.
Since computer-based monitoring systems tended only to produce information useful only to supervisors in evaluating a driver's performance, they became very unpopular with drivers. Such systems were seen as "tattletales", useful only in reporting driving errors to the drivers' supervisors. To retaliate, some drivers would even disable or damage the monitoring systems while others would modify the monitoring systems to falsify the results.
Numerous vehicle monitoring systems which detect and record information related to vehicle operation for later analysis are known. In general, however, a driver interacts with such monitoring systems only to provide additional data for recording. The collected data would neither be available to nor analyzed for the driver. For example, U.S. Pat. No. 4,067,061 to Juhasz discloses a vehicle monitoring and recording system which records the mileage travelled, the fuel consumed and the elapsed time on a tape cassette. At the end of a trip, the recorded information is transferred to a computer for display of information related to the mileage and fuel consumption of the vehicle. Similarly, U.S. Pat. No. 4,072,850 to McGlynn discloses a system for monitoring the usage of a vehicle. In McGlynn, data useful in determining the usage of the vehicle would be automatically collected and recorded on magnetic tape. Later, the recorded data would be transferred to an external computer system for processing. U.S. Pat. No. 4,188,618 to Weisbart discloses a vehicle monitoring system which detects numerous vehicle performance characteristics including vehicle speed, elapsed trip distance, engine rpm, total engine revolutions, total fuel consumption, rate of fuel consumption and the like as a function of time. There data are stored in an on-board memory for later transfer to a fixed base computer for processing of the collected vehicle performance information.
Numerous vehicle monitoring systems which provide information related to the operating characteristics of the vehicle to the driver are also known. One such system may be seen in U.S. Pat. No. 4,093,939 to Mitchell. Mitchell discloses a vehicle monitoring system having sensors for determining if the vehicle speed, engine operating speed and/or the acceleration exceed corresponding threshold values. An alarm is activated to alert the driver when a threshold value has been or is about to be exceeded, thereby resulting in the operation of the vehicle under "abusive" conditions. The amount of time that the vehicle is operated under one or more "abusive" conditions is also recorded. Mitchell additionally provides for recording the total time during which the vehicle is in motion as well as the total time during which the engine is in operation.
However, the particular operating characteristic information which has been supplied to the driver by prior art vehicle monitoring systems does not provide the information which is most useful in determining whether the vehicle is being operated improperly. For example, while the total time during which the vehicle operates at excess speeds provides information regarding the driver's compliance with speed regulations, an excess speed recorder also can mislead a truck company manager as to whether the vehicle has been operated under excessive conditions. Downhill stretches of road tend to promote excess speed conditions even while the vehicle is otherwise being operated normally. Uphill stretches of road, on the other hand, tend to promote excessive engine operating conditions despite vehicle speeds well within the desired operating range. For the same reason, the total time at which the vehicle accelerates at an excessive rate may be misleading as to whether the vehicle has been operated properly. The total time during which the engine has operated at an excessive engine speed, on the other hand, is not the most direct method of measuring engine operation and may not always be the best indicator of improper driving habits such as a habit of excessively accelerating the vehicle.
While devices which measure the manifold pressure of a vehicle engine are known, there have been only limited applications of data related to manifold pressure being collected and provided to the driver as an indicator of the improper operation of the vehicle. Prior uses of information related to the manifold pressure have been directed primarily towards the collection of non-cumulative information, and more particularly non-cumulative fuel consumption information. U.S. Pat. No. 3,812,710 issued to Bauman discloses a device which uses manifold pressure and other engine parameters to produce an electrical output indicative of fuel consumption, distance travelled and time travelled. The output of the Bauman device is a variable output which drives a meter to display increases or decreases in fuel mileage. U.S. Pat. No. 4,067,232 to Murray discloses a system which monitors pressure and vacuum to mechanically operate a switch which shows changes in the rate of fuel consumption utilizing a set of colored lights.
Finally, prior vehicle performance monitoring systems have never been configured to permit the driver to readily determine the detailed information most closely related to the operating efficiency of the vehicle during a trip so that much information can be readily forwarded by the driver to the trucking company office, for example orally over a phone, for the immediate analysis of both the efficiency of the vehicle and the driver.